The word “Hygro” refers to the phenomenon of absorption of water or moisture by yarns and fabrics including towels and toweling fabrics. The fabrics Terry woven and Terry woven toweling are made from, for example, 100% cotton yarns; blends of cotton and viscose; blends of cotton, blends of silk and modal; bamboo fiber yarns; and blends of cotton and bamboo yarns. Flat fabrics, such as sheeting, may be made from 100% cotton; blends of polyester and cotton; blends of polyester and viscose; blends of cotton and modal; blends of cotton, silk and modal; and any combinations thereof.
Most fibers have absorbent properties, and the extent of absorption depends on the type of fiber, their blends and the structure of the yarn made thereof.
By suitable modifications in the yarn structure, it is possible to increase the wicking property of the yarn, in effect increasing the hydrophilic nature, thereby making the yarns quick absorbing and bulky.
The amount of twist in the yarn affects the properties of the towel products. The pile yarn is generally a low-twist yarn. Pile loops provide maximum surface area for the absorption of water, and the low twist aids in the absorption by imparting wicking properties to the yarn. Ground warp and weft are generally hard-twisted compared to the pile yarn. The ground and weft yarn twist factors generally range from about 3.8 to about 4.2, depending upon the towel construction. In contrast, the twist factor in the pile yarn generally ranges from about 3.2 to about 3.8. Similarly in the case of flat fabrics the twist factor for warp and weft range from about 3.8 to about 4.5.
Towels are generally thick materials. The thicker the towel, the greater the surface area, and thus a greater amount of water can be absorbed. When a towel fabric encounters a water droplet, the pile loops first remove the droplet by sucking the droplet between the space available among the pile loops and then absorbing the water inside the yarn in the space between the fibers in the yarn. The latter part is true to flat fabrics as well. The absorbed water then enters the lumen of the cotton fiber.
Normally the yarns used in terry fabrics are coarse and range from Ne (Number English) 8s to 30s in single as well as doubled configuration for pile, weft and ground yarns. The coarse yarn has a greater number of fibers in the cross section. Similarly the warp and weft yarn count, in the case of flat fabrics range from Ne. 12s to Ne. 100s in single as well as doubled configuration depending on the construction
The yarns used in terry fabrics are all cotton except for yarns used in decorative designs and embellishments on the fabric. For example, the yarns used in towels are about 15-30 grams of a total towel weight of about 420-500 grams.
Decorative designs and embellishments are formed using polyester filament, polyester spun yarn, viscose filament yarn, viscose spun yarn, mercerized cotton yarn, modal yarns, chenille yarn, modified viscose yarn, and combinations thereof. Other flat fabrics such as sheeting are made from 100% cotton; blends of polyester and cotton; blends of polyester and viscose; blends of cotton and modal, blends of cotton and silk and modal; blends of cotton and bamboo; blends of cotton and sea weed fibers; blends of cotton and silver fibers; blends of cotton and charcoal fibers; and any combinations thereof.
The greater the amount of free air space available within the yarn, the quicker and more complete the absorption of the water. Hence, to increase the amount of free space, (similarly as the air space increases the drying of the towel after absorption also increases) structural changes in the yarn have to be made.
Polyvinyl alcohol (“PVA”), a man made fiber, has the unique property of dissolving in hot water. This invention exploits the dissolving property of PVA by introducing PVA into blended yarns and, for example, the core of cotton yarn.
During the course of exploring possible method of introducing PVA into cotton yarn via cotton spinning system, three methods were considered.                a) Inserting PVA fibers into the core during ring spinning, by inserting PVA spun yarn into the stream of cotton fibers in the drafting zone during ring spinning. As there was a tendency of the cotton fibers in the outer sheath to slide and form bunches during the weaving process, this required further exploration.        b) Blending PVA fiber slivers along with cotton fiber slivers in the draw frame of a cotton spinning system. As the fibers were homogeneously blended in this process, the proper configuration of PVA fibers in the core could not be achieved.        c) Inserting PVA fiber slivers into the middle of cotton slivers at the feeding end of the drafting zone of the speed frame, twisting on the speed frame, and subsequently spinning the yarn at ring spinning. This was considered a potential system after trial and error refinements were made.The current invention pertains to this successful process of inserting PVA fibers in the core of cotton sheath.        
Therefore it is an object of the invention to provide a method for making a yarn that can be used to form soft terry fabrics or flat fabrics, which are highly hydrophilic in nature and bulky (herein referred to as “Hygro Towels” or “Hygro Toweling Fabrics” or “Hygro fabrics” or “Hygro flat fabrics”). Such highly hydrophilic yarns and fabrics can absorb, for example, between about 65% and 75% of the water contacting the yarn or fabric. In a preferred embodiment, the highly hydrophilic yarns and fabrics of the present invention can absorb between about 65% and 75% of the water contacting the yarn or fabric. In another embodiment the hydrophilic yarns and fabrics can absorb more than 75% of the water contacting the yarn or fabric.
It is a further object of the invention to provide a method for making Hygro Toweling Fabrics and Hygro flat fabrics.
It is a further object of the invention to provide terry fabrics and flat fabrics that are highly absorbent, quick drying, increase in bulk after drying, and have a lower tendency to lint.